The present invention relates to a lane-keep control system and method for a vehicle.
A conventional lane-keep control system is configured to produce, based on a lane condition and a traveling condition of a vehicle, such a steering torque that forces the vehicle to follow a traveling lane and thereby guides a driver to lane-keeping, while being configured to control a deviation amount of front wheels from a guided course in accordance with a detection value of a steering torque sensor and transmitting to the driver a steering reaction force corresponding the deviation amount as disclosed in Unexamined Japanese Patent Publication No. 9-207800.
In the lane-keep control system, during the time a steering angle caused by the driver is small, the deviation amount is set smaller by using a relatively small gain. On the other hand, during the time the steering angle is relatively large, the deviation amount is set larger by using a relatively large gain. This enables the vehicle to follow the lane stably when the steering angle is small while enabling the vehicle to change the lane easily when the steering angle is large.